Inline optoelectronic converter and associated methods

ABSTRACT

An inline optoelectronic converter configured to convert electrical signals to optical signals and to convert optical signals to electrical signals. The converter is external to the avionic computer and connected to the avionic computer at a location spaced apart from the avionic computer. The converter is configured to be integrated into an existing wiring bundle of the avionic computer. Also disclosed is a method of retrofitting an avionic computer by connecting an optoelectronic converter to the computer. The method comprises connecting the converter to an existing wiring bundle of the avionic computer at a location spaced apart from the avionic computer.

TECHNICAL FIELD

The present disclosure relates to an optoelectronic converter. Incertain embodiments, the optoelectronic converter is configured for usewith an avionic computer and associated wiring aircraft installations.

BACKGROUND

In modern aircraft, avionic computers (also known as line replaceableunits (LRUs)) typically include an optical transceiver to enable opticalfiber communication with other LRUs. An optical connector on a housingof the computer enables an optical fiber cable to be connected to thecomputer. Older aircraft, however, typically do not include opticaltransceivers. These aircraft rely on electrical wiring for the transferof data between LRUs. Optical fiber cable, however, has certainadvantages over electrical wiring. For example, optical fiber cable canmitigate electromagnetic interference and reduce wiring weight. Thus, itis advantageous to retrofit airplanes to provide an optical transceiverfor the avionic computer. However, retrofitting that involves placingthe optical transceiver inside the avionic computer is in many casescost prohibitive due to the high cost of redesign and recertification ofthe avionic computer.

Many solutions exist for adding an optoelectronic converter outside ofan LRU. These solutions may include 1) incorporating the converterinside the LRU/aircraft mating connector, on the LRU connector side; 2)incorporating the converter inside the LRU/aircraft mating connector, onthe aircraft connector side; 3) incorporating the converter on thestanchion disconnect (LRU equipment bay back wall); and 4) incorporatingthe converter inside the wire integration panel (WIP).

SUMMARY

The embodiments of the present inline optoelectronic converter andassociated methods have several features, no single one of which issolely responsible for their desirable attributes. Without limiting thescope of the present embodiments as expressed by the claims that follow,their more prominent features now will be discussed briefly. Afterconsidering this discussion, and particularly after reading the sectionentitled “Detailed Description,” one will understand how the features ofthe present embodiments provide advantages These advantages include theability to retrofit existing avionic computers without the need toprovide a separate DC-to-DC power converter, without the need to modifyany onboard circuitry of the avionic computer, and without the need tomodify any connector pin configuration of the avionic computer.

One aspect of the present optoelectronic converter and associatedmethods includes the realization that existing solutions forretrofitting an LRU by adding an optoelectronic converter havedrawbacks. For example, with reference to the solutions discussed in theprevious section, solution 1) requires changes to the LRU interfacecircuitry and pin configuration. Any changes made to the LRU requirethat the LRU be recertified before it can be put back into service. Thisprocess is time consuming and expensive. Further, legacy LRUs aresometimes required to remain unmodified so that they can be soldeconomically as a common standard design to different aircraftplatforms. Solution 2) requires the aircraft to provide a DC-DCconverter for each optoelectronic converter and long power wires thatsuffer voltage drops due to low 5 VDC or less requirement Solution 3)also requires the aircraft to provide a dedicated power supply for theconverter Further, remotely located LRU's don't have a stanchiondisconnect panel, and therefore there is no place to mount the converterand power supply. Solution 4) requires long electrical wiring from theLRU to the WIP, which is susceptible to high intensity radio frequencyinterference and lightning interference and, therefore, defeats thepurpose of converting to optical fiber.

One embodiment of the present inline optoelectronic converter isconfigured to convert electrical signals to optical signals and toconvert optical signals to electrical signals. The converter compriseselectrical wiring extending between the converter and an avioniccomputer or between the converter and a connector associated with theavionic computer. The converter further comprises an opticaltransceiver, a voltage regulator, an electrostatic and electromagneticinterference filter, an optical fiber cable, and an optical fiberterminal. The converter is external to the avionic computer and thewiring operatively connects the converter to the avionic computer at alocation spaced apart from the avionic computer. The optoelectronicconverter is configured to be integrated into a wiring bundle connectedto the avionic computer or the connector. A single power source providespower to both the avionic computer and the optoelectronic converter.

One embodiment of the present methods comprises a method of retrofittingan avionic computer by connecting an optoelectronic converter to thecomputer. The optoelectronic converter is configured to convertelectrical signals to optical signals and to convert optical signals toelectrical signals. The method comprises connecting converter powerwiring from the optoelectronic converter to existing power wiring fromthe avionic computer by splicing the converter power wiring into theexisting power wiring, or by double staking the converter power wiringwith the existing power wiring. The method further comprises cuttingexisting data wiring from the avionic computer and connecting theexisting data wiring to the optoelectronic converter. The method furthercomprises securing the optoelectronic converter to an existing wiringbundle of the avionic computer at a location spaced apart from theavionic computer.

One embodiment of the present hybrid electrical/optical aircraft datanetwork comprises a first avionic computer and a second avioniccomputer. The hybrid data network further comprises a firstoptoelectronic converter associated with the first avionic computer andspaced apart from the first avionic computer. The hybrid data networkfurther comprises a second optoelectronic converter associated with thesecond avionic computer and spaced apart from the second avioniccomputer. The hybrid data network further comprises first electricalwiring connecting the first avionic computer with the firstoptoelectronic converter. The hybrid data network farther comprisessecond electrical wiring connecting the second avionic computer with thesecond optoelectronic converter. The hybrid data network furthercomprises an optical fiber cable connecting the first optoelectronicconverter with the second optoelectronic converter. The firstoptoelectronic converter and the first avionic computer are connected toa first common power source, and the second optoelectronic converter andthe second avionic computer are connected to a second common powersource.

The features, functions, and advantages of the present embodiments canbe achieved independently in various embodiments, or may be combined inyet other embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the present optoelectronic converter and associatedmethods now will be discussed in detail with an emphasis on highlightingthe advantageous features. These embodiments depict the novel andnon-obvious optoelectronic converter shown in the accompanying drawings,which are for illustrative purposes only. These drawings include thefollowing figures, in which like numerals indicate like parts:

FIG. 1 is a schematic block diagram of a prior art avionic computer;

FIG. 2 is a schematic block diagram of one embodiment of the presentoptoelectronic converter connected to an avionic computer;

FIG. 3 is a plan view of one embodiment of the present optoelectronicconverter connected to electrical wiring and connectors;

FIGS. 4 and 5 are schematic block diagrams of alternative embodiments ofthe present optoelectronic converter; and

FIG. 6 is a flowchart illustrating the steps in one embodiment of thecurrent methods associated with an inline optoelectronic converter.

DETAILED DESCRIPTION

The following detailed description describes the present embodimentswith reference to the drawings. In the drawings, reference numbers labelelements of the present embodiments. These reference numbers arereproduced below in connection with the discussion of the correspondingdrawing features.

FIG. 1 illustrates a schematic block diagram of a prior art avioniccomputer 10. An electrical wiring bundle 12 extends from the computer10. A connector 14 enables quick connect/disconnect of the wires 12 fromthe computer 10. The wires 12 are divided into electric power carryingwires 16 and data signal carrying wires 18. The power wires 16 carryelectric power from an external source (not shown) to the computer 10.The data wires 18 carry data signals between the computer 10 and variousother computers throughout the aircraft (not shown). As used herein, theterm data wire is to be construed broadly to include any medium capableof transmitting data, such as data buses and wires capable of carryinganalog signals, discrete signals, and digital signals.

Many existing aircraft include an avionic computer 10 of the typeillustrated in FIG. 1. It is advantageous to retrofit these computers toadd an optoelectronic converter so that the computer 10 can communicatewith another computer onboard the aircraft over an optical fiber cable.For example, optical fiber cable can mitigate electromagneticinterference and reduce wiling weight. However, existing retrofittingmethods require modification of the computer 10, such as changes to thecomputer's onboard circuitry and connector pin configuration. Redesignand recertification of an avionic computer is a time consuming andexpensive process. The present embodiments provide an optoelectronicconverter that can be integrated into the aircraft wiring bundle so thatno changes to the computer 10 are necessary.

FIG. 2 is a schematic block diagram of one embodiment of the presentoptoelectronic converter 20 integrated into the wiring bundle 12 of anavionic computer 10. FIG. 3 is a plan view of the converter 20integrated into the wiring bundle 12. In FIGS. 2 and 3, components thatare identical to those of FIG. 1 include like numbering. Thus, asdescribed above, the illustrated assembly includes an avionic computer10 (FIG. 2) and a connector 14 (FIGS. 2 and 3) that enables quickconnect/disconnect of the wires 12 from the computer 10. FIG. 3 alsoillustrates a connector 22 configured to connect the power wiring 16 toa power source (not shown).

With reference to FIGS. 2 and 3, the converter 20 is a self-containedcapsule that is spaced apart from the computer 10, and that connectsdirectly to the existing electrical wiring bundle 12. As shown in FIG.2, power wires 24 associated with the converter 20 may be spliced intocorresponding power wires 16 associated with the computer 10. Ratherthan splicing, the power wires 24 associated with the converter 20 couldbe double-staked with the power wires 16 at the terminals 28 on theconnector 14. Data wires 26 extend between the terminals 28 on theconnector 14 and converter 20. As indicated, the data wires 26 aremembers of the group of existing wires 18 associated with the LRU 10prior to the installation of the converter 20.

With continued reference to FIGS. 2 and 3, the converter power wires 24connect to the computer power wires 16 to tap into the electrical powercarried therein and supply power the converter 20. The converter datawires 26 carry electrical data signals between the computer 10 and theconverter 20. The converter 20 converts these electrical data signalsinto optical data signals that are then transmitted to another computeronboard the aircraft (not shown) over an optical fiber cable 30. Theremaining computer data wires 18 not connected to the converter 20 maycontinue to function as they had prior to the installation of theconverter 20. For example, these wires may carry electrical signals,such as discrete analog signals, to other avionic computers (not shown).Alternatively, these wires may be used to install additionaloptoelectronic converters similar to the converter 20.

As indicated, the LRU 11 communicates with other LRUs (not shown) aboardan aircraft. Thus, in one embodiment FIG. 2 illustrates one half of ahybrid electrical/optical aircraft data network. The other half of thehybrid data network comprises a mirror image of FIG. 2. The illustratedLRU 10 communicates with the LRU at the opposite end of the systemthrough the data wires 26, the converter 20 and the optical fiber 30. Asecond converter 20 at the opposite end of the system receives signalstransmitted over the optical fiber 30, converts those optical signals toelectrical signals, and transmits those electrical signals to the secondLRU over data wires.

FIG. 4 illustrates a schematic block diagram of a first configurationfor the optoelectronic converter 20. A capsule or housing 32 containsthe components of the converter 20. In certain embodiments, the capsule32 may be constructed of metal and hermetically sealed to protectsensitive components inside, such as photonics, from radiatedelectromagnetic interference, dust, moisture, etc., which are typicallypresent in an aircraft environment.

With continued reference to FIG. 4, an optical transceiver 34 within thecapsule 32 is configured to convert electrical signals from the avioniccomputer 10 to optical signals using a light source and driver (notshown). The optical transceiver 34 is further configured to receiveoptical signals using a light detector and amplifier (not shown), and toconvert those signals to electrical signals for input into the avioniccomputer 10. The optical transceiver may use two optical fibers fortransmit and receive separately, or employ a multiplexer/demultiplexer(not shown) to combine the optical input and output signals onto asingle optical fiber.

Depending upon the light source selected, the optical fiber may be glassor plastic, and single mode or multimode. The optical fiber cable 30connects to an optical fiber terminal 36, which in turn connects to theoptical transceiver 34. Because the optical fiber terminal 36 iscontained within the capsule 32, it is advantageously protected fromdust contamination. The optical fiber cable 30 carries data signalsbetween the avionic computer 10 and another computer onboard theaircraft. In certain embodiments, the optical fiber cable 30 may be asingle bidirectional fiber, which advantageously reduces by half theneeded amount of fibers and mating connectors, which in turn reducesweight, cost, volume, and installation labor.

With continued reference to FIG. 4, electrical wiring 24, 26 extendsbetween the converter 20 and the computer 10 (or a connector 14connected to the computer 10), as described above with respect to FIG.2. The wires 24, 26 connect to an electrostatic and electromagneticinterference filter 38 configured to reduce electrical noise within theconverter 20. Additional data wires 27 connect the filter 38 with theoptical transceiver 34. The data wires 26, 27 may comprise transmitdata, receive data, transmit enable, as well as other control and alarmsignals. Additional power wires 29 connect the filter 38 with theoptical transceiver 34 through a voltage regulator 40, which convertsthe existing power supplied to the computer 10 to a suitable voltage forpowering the converter 20. In one embodiment, for example, the voltageregulator 40 may receive an input of 0-40 VDC and produce an output of 5VDC±2 VDC. In another embodiment, the voltage regulator may receive aninput of 28 VDC and produce an output of 3 VDC. Those of ordinary skillin the art will appreciate that other voltages could be provided, andthe current could be alternating rather than direct.

FIG. 5 illustrates a schematic block diagram of another configurationfor the optoelectronic converter 50. Comparing FIGS. 4 and 5, in theembodiment of FIG. 4 all components of the converter 20 are containedwithin the capsule 32, save for the wiring 24, 26 and cabling 30extending outward from the capsule 32. In the converter 50 of FIG. 5, bycontrast, the filter 38, voltage regulator 40 and optical transceiver 34are contained within the capsule 52, but the optical fiber terminal 36is not. Instead, the optical fiber terminal 36 is supported within afirst connector 54 that is pluggable with the capsule 52. Similarly, thewiring 24, 26 is pluggable with the capsule 52 through a secondconnector 56 including a socket 58. Within the capsule 52, data wiring27 and power wiring 29 interconnect the socket 58, ESD/EMI filter 38,voltage regulator 40, and optical transceiver 34 as shown.

The converter 50 of FIG. 5 can be advantageously quickly connected anddisconnected from the wiring 24, 26 and the optical fiber cable 30 sothat the converter 50 can be quickly replaced in the event itmalfunctions. Rather than intruding upon the wiring 24, 26 and the fiberoptic cable 30 to perform the more time consuming steps of splicing orstaking of wires and cables, the converter 50 can just be unplugged andreplaced with a new converter 50 that can also be quickly plugged in.The couplings 60 between the capsule 52 and the connectors 54, 56 can,for example, be bayonet couplings or threaded couplings.

At least two additional configurations are possible for the presentoptoelectronic converter 20, 50. In one additional configuration (notshown) the converter 50 of FIG. 5 is modified so that the connector 54on the optical side is replaced with the optical side configuration ofthe converter 20 of FIG. 4. In another additional configuration (notshown) the converter 50 of FIG. 5 is modified so that the connector 56on the electrical side is replaced with the electrical sideconfiguration of the converter 20 of FIG. 4.

In certain embodiments, the present optoelectronic converter may be usedwith an LRU that contains more than one data bus. In such embodiments,multiple data buses may be aggregated with a single optoelectronicconverter. However, each data bus would have its own optical converterand would operate on its own unique wavelength. These differentwavelengths could then be readily multiplexed on a single bidirectionalfiber, or on separate transmit and receive fibers.

As described, the present optoelectronic converter provides conversionof electrical data wiring to a single optical fiber cable for existingLRU's by integrating the capsule into the existing aircraft wiringbundle. The capsule is compact enough that it can be integrated withoutthe need for any mounting hardware to hold the capsule in place. Forexample, the capsule can be secured to the wiring bundle itself, such aswith zip ties or other similar fasteners. Its connection to the wiringprovides all the support that is necessary for the capsule. And, thecapsule is self-contained. It includes all of the hardware it needs toallow it to be seamlessly integrated into the existing wiring bundle. Toreduce part count the capsule can be provided with a pigtail of fourwires and an optical fiber cable. Accordingly, the optoelectronicconverter avoids the drawbacks of current apparatus and methods thatrequire the provision of additional infrastructure to accommodate theconverter, such as a low voltage DC-DC converter, an adapter connectorbetween the LRU connector and the converter connector, mounting for theconverter etc. Further, the capsule integrates into the wiring bundle ata location spaced from the LRU. Accordingly, the optoelectronicconverter avoids the drawbacks of current apparatus and methods thatrequire changes to the LRU, such as an adapter connector between the LRUconnector and the converter connector, changes to onboard circuitry ofthe computer, changes to the connector pin configuration of thecomputer, etc.

FIG. 6 illustrates one embodiment of a method for retrofitting an LRUwith the present optoelectronic converter. In step S600 the operatorbegins with the optoelectronic converter and the LRU that is to beretrofitted. In step S602 the operator splices the power wires from theoptoelectronic converter into the existing power wires from the LRU.Alternatively, the operator may double stake the power wires from bothdevices at the LRU or at the connector connected with the LRU. In stepS604 the operator cuts the existing data wires associated with LRU andconnects the cut wires to the optoelectronic converter. Alternatively,the optoelectronic converter may be supplied with its own data wires,which could be spliced with the LRU's existing data wires or staked atthe LRU or at the connector connected with the LRU. In step S606 theoperator secures the optoelectronic converter to LRU's wiring bundle, aswith zip ties or the like.

The above description presents the preferred mode contemplated forcarrying out the present optoelectronic converter and associatedmethods, and of the manner and process of making and using it, in suchfull, clear, concise, and exact terms as to enable any person skilled inthe art to which it pertains to make and use this optoelectronicconverter and these methods. This optoelectronic converter and thesemethods may, however, be modified or constructed differently from thatdiscussed above. These modifications and alternate constructions are,however, fully equivalent. Consequently, this optoelectronic converterand these methods are not limited to the particular embodimentsdisclosed. On the contrary, this optoelectronic converter and thesemethods cover all modifications and alternate constructions comingwithin the spirit and scope of the embodiments as generally expressed bythe following claims, which particularly point out and distinctly claimthe subject matter of the present embodiments.

1. An optoelectronic converter configured to convert electrical signalsto optical signals and to convert optical signals to electrical signals,the converter comprising: electrical wiring extending between theconverter and an avionic computer or between the converter and aconnector associated with the avionic computer; an optical transceiver;a voltage regulator; an electrostatic and electromagnetic interferencefilter; an optical fiber cable; and an optical fiber terminal; whereinthe converter is external to the avionic computer and the wiringoperatively connects the converter to the avionic computer at a locationspaced apart from the avionic computer; further wherein theoptoelectronic converter is configured to be integrated into a wiringbundle connected to the avionic computer or the connector; and furtherwherein a single power source provides power to both the avioniccomputer and the optoelectronic converter.
 2. The optoelectronicconverter of claim 1, further comprising a housing enclosing at leastthe optical transceiver, the voltage regulator and the electrostatic andelectromagnetic interference filter.
 3. The optoelectronic converter ofclaim 2, wherein the housing also encloses the optical fiber terminal.4. The optoelectronic converter of claim 2, further comprising aconnector configured to enable the optical fiber cable to be pluggedinto and unplugged from the converter.
 5. The optoelectronic converterof claim 3, wherein the optical fiber terminal is a component of theconnector, such that when the connector is unplugged from the converterthe optical fiber terminal is also unplugged from the converter.
 6. Theoptoelectronic converter of claim 2, further comprising a connectorconfigured to enable the electrical wiring to be plugged into andunplugged from the converter.
 7. The optoelectronic converter of claim5, wherein the connector includes a socket for receiving a mating memberof the converter.
 8. The optoelectronic converter of claim 2, whereinthe housing is hermetically sealed.
 9. The optoelectronic converter ofclaim 2, wherein a first subset of the electrical wiring carrieselectric power, and a second subset of the electrical wiring carriesdata signals.
 10. The optoelectronic converter of claim 9, wherein thefirst subset of the electrical wiring provides an input voltage to thevoltage regulator.